Hi all,
I currently have an Aritech alarm panel and I would like to use the existing sensors for my domotica system as well.
In line with the alarm sensor two resistors (4k7) are connected. These resistors ( one in parallel with the PIR/REED contact and one serial) make it possible to distinguish between four common states:
o Normal, the alarm contact is closed and everything is normal => 4K7 Ohm
o Triggered, the alarm contact is opened and rest is normal => 10K ohm
o Sabotage, the line has a short circuit => 0 Ohm
o Sabotage, the line is cut => ~ Ohm
For my domotica system I am only interested in two sensor conditions: Normal & Triggered. Sabotage is handled by the alarm panel.
Currenlty I am thinking about buying a VM140 and to use the analog input port to measure the voltage on each input port of my alarm panel. Based on this I should be able to determine the state of the sensors. The only thing I am not sure of is weather using the analogue input ports might influence the input port of the alarm panel (for example because this adds an additoinal resitance or something like that). Anyone experience with this?
Regards,
Peter